GB923770A - Data storage system - Google Patents

Abstract

923,770. Digital electric-calculating. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 14, 1961 [Dec. 30, 1960], No. 44810/61. Class 106 (1). Corresponding orders of selected words in a memory are added directly without removing the words from memory. A bit is stored in a cell 20 by steering current on a line 80, by means of cryotron gates (not shown) to either the right-hand or left-hand path 86, 82, to indicate 0 or 1, respectively. To add all or some of the contents of the cells 20, 22 . . . 36 together with carries from two lower orders, a current is applied to terminal 90 and it is steered through a cryotron gate tree to mark one out of seven lines 60. The value of the line marked is converted into binary form as a sum signal to be applied to a second tree for the next four words in memory, and as carry signals to the next higher orders. Since in the embodiment described only two carries are to be allowed for, each tree has a maximum of seven levels. As shown, to add nine words, two trees are necessary. The upper tree has five inputs from storage cells and two in-carries; the lower tree has the sum input from the coded output of the tree, four inputs from storage cells and two in-carries. The sum output of the lower tree is stored by steering current to either the upper or lower path of a loop in a register 12. If cell 20 is storing 0, cryotron gate 88 is resistive and current on line 90 is steered on to line 91. This sends gate 100 resistive and current from terminal 96 is steered to the righthand branch of the tree. Words to be added are selected by energizing a select or suppress li ne such as 74 associated with each word. If the select line is energized cryotron 93 is resistive and the contents of cell 20 control the setting of the cryotron tree. If the suppress line is energized, gate 94 is resistive and the contents of cell 20 are treated as if they were 0. Thus, current on line 92 representing 1 is switched through gate 93 on to line 91 where its significance is 0. The generation of sum and carry signals takes place in circuit 62. If an odd number representing line is marked, one of cryotrons 111, 113, 115 or 117 is resistive and current on line 109 is steered to the 1 representing sum line. If lines representing 2, 3, 6 or 7 are marked, cryotrons 120 or 128 are resistive and current is steered from line 124 to the 1 incarry line of the next higher order. If lines representing 4, 5, 6 or 7 are marked, the current on these lines is led away as the 1 in-carry line to the next higher order but one. It is stated that photo-resistors and lamps may be used instead of cryotrons. Other arrangements of the in-carries are described. Specification 862,178 is referred to.